7 Causes of Spatter and How to Eliminate It

Mig welding is characterized by sparks and spatter flying all over the place. It looks great on movies, but when we are doing the welding we realize spatter is a bad thing. It creates more work by increasing clean up time, it wastes material, and it can burn you if you are not wearing the right PPE. It is almost impossible to eliminate spatter in MIG welding, but we can certainly reduce it by understanding what causes it in the first place.
Spatter in Welding
Most of us don’t have the option to buy the latest technology in welding equipment to eliminate spatter. We have to weld with what we have. So we are not going to talk about how equipment can help eliminate spatter. This list are items that you can change right now and for free.

7 Causes of Spatter:

1. Incorrect settings – procedures that are out of whack will cause spatter. Amperage, voltage and electrical stick out a crucial.

  • Amperage:

Amperage in GMAW is determined by your wire feed speed. Running amperage that is too high will cause spatter. To correct either lower the amperage by decreasing the wire feed speed or increase the voltage.

  • Voltage:

Per the above, if your voltage is too low your spatter levels will increase. Increase your voltage until spatter decreases.

  • Electric Stick Out (ESO):

Electrical stick out is the distance from your contact tip to the work piece. When mig welding you want to be around 3/4″. A bit more for high amperage. Excessive stick out will increase spatter somewhat, but it will create bigger problems (porosity due to lack of shielding gas and lack of penetration).

2. Work angle too steep – there is a debate on whether pushing or dragging while mig welding is the way to go. Regardless of which you prefer make sure your drag (pull) or push work angle does not exceed about 15 degrees. At times there is no choice if reach is a problem. But when you can control it do not exceed 15 degrees. Steep angles generate a lot of spatter.

3. Surface Contaminants – rust, oil, paint and other surface contaminants will create spatter. Clean surfaces as best as possible prior to welding.

4. Mode of Metal Transfer – Short arc and globular transfers are modes of metal transfer that produce a lot of spatter. To drastically reduce spatter you need to achieve spray transfer. To do this you need a minimum of 83% argon in your shielding mix (a typical mix would be 90/10). However, you also need to be above the transition currents for the diameter of wire you are running. Smaller machines will not be capable of this.

5. Erratic Feeding – when the wire feeder cannot feed wire at a constant speed there will be fluctuations in amperage that will drastically affect the arc causing a lot of spatter. Make sure you don’t have any feeding issues. For help in correcting this problem take a look at Troubleshooting Erratic Wire Feeding.

6. Quality of Consumables – some applications can live with high levels of spatter, others can’t. In robotic applications and other situations in which wire consistency is critical shy away from the cheap-low quality wires. A single spool or drum may be consistent, but across several spools or drums there may be variations in wire diameter, copper coating, and chemistry. Unfortunately AWS allows for such wide range of chemistry that even a coat hanger can be made into a mig wire. The best manufactures keep their own ranges and tolerances and thus produce better product.

7. Bad Shielding Gas – This is very uncommon, but shielding gases of low quality can affect spatter levels. What is more common is mislabeling (i.e. getting a 75/25 on a cylinder that has a 90/10 label), but even this is rare. The higher the argon content the smoother the arc. 100% carbon dioxide is cheap and provides good penetration profile, but it creates a lot of spatter.

If you think it looks too complicated to get rid of spatter take a look at what it can be costing you: The Real Cost of Welding Spatter

Finally a word on anti-spatter. Anti-spatter does not eliminate or prevent spatter. It simply allows the spatter to slide off the material and not stick to it. By using excessive amounts you can introduce other problems such as porosity. It is not bad to use it, but look into what’s causing spatter in the first place and take care of it.

Sources: AWS D1.1/D1.1M:2006 Structural Welding Code

The Procedure Handbook of Arc Welding, 14th Edition

Please note: I reserve the right to delete comments that are offensive or off-topic.

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30 thoughts on “7 Causes of Spatter and How to Eliminate It

  1. The arc doesn’t initiate a good weld, it spatters and putters about, endlessly sometimes… Stopping, then starting again helps SOME of the time, but not all the time.. during a weld, it will start to spatter out of the blue…
    Sometimes, the spatter will pop around like pop corn (sound and action) or sometimes produce a small runny looking weld then a bead..

    Any help would be cool..

    • When you get that kind of a start typically you are welding using GMAW in the short circuit or globular transfer. There isn’t enough voltage to burn off the wire properly and you get stubbing of the wire. Check the following:
      1. Is the setting adequate – increase your voltage if necessary
      2. If the settings are adequate there may be a voltage drop in the system. Make sure your cables are in good repair, all connections are tight and that the cables (electrode and work cables) are properly sized.
      3. If the machine has “arc control” you may be able to play with it to get a better start.
      4. In some cases this erratic start is caused by too high of a wire feed speed for a clean start. If your machine is equipped with the option “run-in wire feed speed” use it. Turn this speed down to about 50-100ipm. If this is not an option increasing your voltage a bit may be your best choice, just make sure it does not cause issues with the weld such as undercut.
      5. Make sure you are not having feeding problems. For things to check in this regard read: Troubleshooting Erratic Wire Feeding.

  2. When we weld a pipe through Co2 welding procedures.
    Mig nozzle get welded with the base and it sounds small blast. It creats sounds and doesn’t weld nice
    What can be the solution?

    • You nozzle gets welded to the base material? If this is the case you are probably dipping the nozzle into the welding puddle and fusing it to the weld. If you are talking about a spatter ring forming in the nozzle which then drops into the weld this is a common problem. It is due to a buildup of spatter in your nozzle. CO2 generates a lot of spatter so changing procedures doesn’t change that. You may be able to use a coating gel for the nozzle (Nozzle Dip) to prevent spatter from sticking to it,or you can clean your nozzle out on regular intervals before the spatter ring falls out of on its own.
      Lastly, if you mean that the nozzle gets welded to the base of the gun (to the diffuser) you may just need to make sure it is screwed on tight.

  3. Good information especially about the angle of weld and the distance of the tip of the welder and the medium that is being welded!! Both tips have really helped! Thank you!!

  4. My question is how to find the adequate settings for your CO2 welding machine like Voltage , Current and wire feed speed?

    • CO2 is a great gas to weld with due to its relatively low costs and great performance over rust and mill scale. It also gives broad penetration profile which makes it more forgiving when reaching the root is critical. However, it is the shielding gas that will give you more spatter. In order to minimize spatter you need to set the best procedures possible. Unfortunately, this also means that the colder procedures (lower WFS and Voltage) will give you less spatter, but also hurt your speed. The optimal WFS (amperage) and voltage depends on the wire diameter you are running, the thickness of the base metal, and the type of joint. If you can provide these details we can provide starting procedures.

      One method to reduce spatter if you already have the best welding procedure is to run a gas-shielded flux-cored wire designed to run with CO2. The slag that forms during welding provides a more stable arc and minimizes spatter significantly. The cost however, is higher than solid wire.

      • I am using HTW-50 copper coated mild steel solid wire. Its dia is 1 mm.
        Shielding gas is 100% CO2.
        Now can u tell me about the proper electrical settings for this type of wire?

        • The actual procedure will depend on the material thickness. But a good range for using 1mm (0.040″) diameter solid wire is from 2.7m/min to 5.5m/min (about 110 to 225 inches/minute) with voltage ranging from 18 to 22 vols. You can certainly go beyond these numbers, but the arc may bet a bit violent and erratic.

          • I am using New Generation Thristor Controlled CO2/MAG Welding Machine
            XD-350S. It has a knob of voltage and current only. It doesnt have a knob wire feeding speed.so how would i set my wire feeding speed when i have a knob of current? and what would be the recommended current in this situation?

          • The wire feed speed range of 2.7 to 5.5 m/min is approximately 110 to 185 amps. Keep in mind that the mig weldign machine will keep voltage constant (at whatever value you set) but it will adjust amperage to do so. Changes in your contact tip to work distance will affect amperage. If you pull a long arc your amperage will go down.

          • I dont have a control on WFS on this MIG welding machine. but i can control current. So If a gave a curent of 180 A, will WFS automatically adjust itself a/c to this current?
            And i am welding parts of different thicknesses on different positions and it ranges from 1.5mm to 4mm.
            using 1mm wire electrode and 100% CO2 shielding gas. What will be the optimum value of current in this situation? (Because I have knob of current and not WFS)

          • The optimal current depends on the thickness of the material and the position. On 4mm and in the flat position you can be towards the top, around 180amp. If you are welding the thinner material adjust it downward. You will want to set your voltage based on the arc. The wire should not stub onto the material when trying to weld,it should have a nice crisp sound.

          • I want to ask another thing. Can i measure output current in GMAW with DC clamp meter by inserting lead (which is connected with the gun) into the jaws of clamp meter.
            Will it give accurate reading or is there any other method to measure the output current in GMAW?

          • Not exactly sure of the location you are describing. The most accurate will be obtain by getting as close to the arc as possible. The contact tip would be ideal, but we would melt the meter’s clamp. The closest place to clamp on is where the weld cable goes into the handle of the mig gun. If you have a leads that are pointed instead of clamps it becomes a lot easier, just poke through the rubber sheath on the weld gun assembly cable. The other end can be placed at the work (ground) clamp.

  5. We weld aluminum beam with end caps on either side using MIG.
    How to avoid splatter losses and black soot formed?
    Can I cover the unwelded portion of the beam with some material so that splatter falls on it and the soot can be cleaned by buff pad ?
    Please give some fool proof method.
    My manager is pressurising me.

    • What filler metal are you using? If you are using 5356 and could go to a 4043 it will produce less soot. However, make sure this is an acceptable change. Also, soot is made worse by lack of shielding gas and incorrect torch angle. If you need to eliminate soot you must run a push angle of 5-15 degrees. If you are getting a lot of spatter your welding procedures may be inadequate, your fit up may not be good, or your base material is not clean.
      Can you tell us what your procedure looks like?
      Joint details (joint type, base material, base material thickness, any prep such as wire brushing or acetone)
      Weld procedure (wire feed speed, filler metal type, filler metal diameter, voltage, shilding gas, gas flow rate, contact-tip-to-work distance, travel and work angles). With this information we should be able to provide better recommendations.